Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
From: Grafton, MA
Region: Northeast
Topic: Diseases and Disorders
Title: Strange growth on oak tree
Answered by: Nan Hampton
It sounds as if your tree has a gall. This is a growth that the tree makes in response to an insect or another organism such as a mite or a fungus. Many galls are caused by an insect laying its eggs in the tree. The insect hatches inside the gall growth, feeds on the growth and then emerges from the gall to continue its life cycle. Here is more information about oak galls from the University of Kentucky and here is a Gallery of Common Galls from North Carolina State University. Your growth sounds a bit like a horned oak gall. If you don't find your growth in one of these links, please send us a photo and we will do our best to identify it. Please visit the Ask Mr. Smarty Plants Plant Identification page to read instructions for submitting photos.
Note from Mr. SP: After this answer was posted, someone else sent us a photograph that sounds very much like the gall described above. We submitted the photo to BugGuide.net and asked if anyone could identify it. Someone did identify it as being made by a gall wasp, Adleria quercusstrobilana, in the (Family Cynipidae), laying its eggs in the stem of the tree.
Yellowing leaves on young bur oak
August 06, 2007 - I saw your response on 7/25 about leaves on mature live oaks turning yellow, then brown because of excessive rain. The same thing is happening to our young burr oak. Leaves are turning yellowish, th...
view the full question and answer
Yellowing of St. Augustine grass in south Texas
June 04, 2009 - We live in deep south Texas, Roma, Texas to be precise and we have a problem with our San Augustine grass. In the spring its quite nice and green after a few weeks and one rain it is turning yellow.
view the full question and answer
Problems with gnats in dirt
December 27, 2008 - I have problems with gnats in my dirt. It's something I can't get control of. What can I do?
view the full question and answer
Mountain laurel (Sophora secundiflora) refuses to bloom
March 07, 2008 - We have a Texas Mountain Laurel that gets full sunlight, but does not bloom. It is 4-5 ft tall & 3-4 ft wide & healthy. Is there anything we can do to make it bloom next year?
view the full question and answer
Black Sooty Mold on Bay Tree
February 25, 2013 - I have a large bay tree and all the leaves are covered with a black mold-like substance on the top part of the leaf. Under each leaf are some black/brown spots. I have washed the leaves with soap and ...
view the full question and answer
![]() |
Support the Wildflower Center by Donating Online or Becoming a Member today. Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends. |